This invention relates to a two-piece electrical connector for electrically connecting two printed circuit boards (PCBs) to each other and, in particular, to an electrical connector member having a flexible contact member such as an FPC (flexible printed circuit), an FFC (flexible flat cable) or the like to be inserted into a mating connector member under a ZIF (zero insertion force).
A known two-piece electrical connector of a ZIF type using FPCs as contact members is disclosed in Japanese Unexamined Patent Publication No. JP-A 8-330031 (330031/1996) corresponding to U.S. patent application with a Ser. No. 08/991,102 filed on Dec. 12, 1997. The known two-piece electrical connector is for electrically connecting first and second PCBs and comprises a combination of first and second (or mating) connector members to be connected to the first and the second PCBs, respectively.
The first connector member comprises a pair of first FPCs as two contact rows of a plurality of contact elements. Each of the first FPCs has a first end connected to the first PCB and a second end opposite to the first end and brought into contact with contacts of the second connector member. A pair of elastic plates are fixed to the second ends of the first FPCs, respectively.
The second connector member has a projection and a contact holding portion. The contact holding portion is provided with a pair of grooves in which the contacts are disposed to be exposed in end walls of the grooves. Each groove loosely receives the second end of each of the first FPCs when the first and the second connector members are mated. Simultaneously, the projection engages and urges each of the elastic plates to bring the second end of each of the first FPCs into press contact with the contacts of the second connector member.
In the known two-piece connector, if the contact holding portion is fixedly mounted at a level in the second connector member, a stature of the two-piece connector in a mated condition on the second PCB is almost equal to a total of a length of the first FPC and the level of the contact holding portion.
In a specific example of the known two-piece connector, the contact holding portion is movable along the projection. The second connector member further comprises a pair of second FPCs having first ends connected to the contacts in the contact holding portion and the second ends connected to a conductive portion of the second PCB to establish electrical connection therebetween.
In the specific example, when the second connector member is coupled to the first connector member, the contact holding portion moves downward to thereby bend or deform the second FPCs. Therefore, the stature of the two-piece connector in the mated condition on the second PCB is reduced. On the other hand, when the second connector member is separated or disconnected from the first connector member, the contact holding portion is moved upward. Following the downward and upward movement of the contact holding portion, the second FPCs are deformed and bent. The deformation may often cause breakage of mechanical and electrical connection between the second ends of the second FPCs and conductive patterns on the second PCB established by soldering. Thus, the reliability of mechanical and electrical connection is decreased. In addition, when the second FPCs are bent, stress is concentrated to the first and the second ends of the second FPCs connected to the contacts in the contact holding portion and the conductive patterns of the second PCB, respectively. This may result in breakage of the conductive patterns at the first and second ends of the second FPCs.